Millions of Americans will face 'life-threatening' cold that can cause frostbite within minutes as an arctic blast sweeps through over Christmas weekend

• Tens of millions of Americans are under winter weather warnings ahead of the holiday weekend.
• Sub-zero temperatures and strong winds pose a significant danger to those outside.

"Astronomical winter" conditions are headed for nearly every state in the country ahead of the holiday weekend, according to the National Weather Service.

Arctic blizzards, below-freezing temperatures, and intense winds beginning Wednesday are forecast to impact millions of Americans from the Pacific Northwest to the Appalachian Mountains through Saturday afternoon, the government agency said in a notice.

More than 90 million people across 37 states are under weather alerts, in what the National Weather Service is calling a "once in a generation type event," with states as far south as Texas bracing for icy conditions, CNN reported.

A wall of "dangerous" arctic air sweeping through the US from Western Canada could bring heavy snow in the Northwest and Rocky Mountains, while the Midwest faces possible blizzard conditions and "life-threatening" wind chills before the storm swings eastward.

According to the National Weather Service, temperatures in the Great Plains could reach as low as -30 degrees Fahrenheit, while wind gusts of up to 60 miles per hour could hit the central and north-central US with temperatures as low as -40 degrees Fahrenheit.

The agency warned this week that such conditions can be life-threatening and lead to frostbite in just 10 minutes, leaving shelters across the country scrambling to prepare for the dangerous weather.

Central Iowa Shelter & Services in Des Moines, Iowa, where temperatures are expected to dip below zero several times this weekend, is already at full bed capacity, a staffer told Insider.

"It's freezing out there," Verna Williams said. "We are not turning anyone away. Everyone needs somewhere to get warm."

The shelter plans to continue helping walk-ins even as their numbers grow, Williams said, finding chairs and tables for people to use once the beds are gone. She said there were about 260 people already at the shelter as of Wednesday evening.

"Just making sure that they're able to be safe, and have some warmth, have somewhere for safety, have somewhere to get something to eat and drink," she told Insider.

Staffers are working overtime to handle the extreme weather. Williams said it was an "all hands and toes" on deck type of situation: "We're all in out here."

Shelters in the mid-west are also preparing for sub-zero temperatures and working to get unhoused people off the streets and inside, Perry Hines, chief development officer at Wheeler Mission in Indianapolis told Insider.

"During this bitter cold, our neighbors experiencing homelessness are at risk of frostbite, hypothermia, or even death," Hines said. "The danger is real and we are here to help."

Hines said the organization's shelters were only at 75% capacity as of Wednesday evening and had room for additional men, women, and children to come in and get out of the cold.

The winter conditions are also almost certain to cause travel nightmares across the country during one of the busiest travel weekends of the year. Between icy roads, airport delays, and possible power outages, travel is expected to be near-impossible in many places, the National Weather Service warned.